The Yankees are proceeding with caution when it comes to Joba Chamberlain's injured left oblique.

New York has shut down the former top prospect for the time being, after an MRI exam on Sunday revealed that damage to the the right-hander's left oblique may have been worse than the team originally expected, reports the New York Post.

Chamberlain's next appearance (which was scheduled to be Wednesday or Thursday) has been pushed back indefinitely after the reliever felt discomfort in his abdomen during a spring training outing on Friday.

"Whenever anyone's dealing with an oblique, there's a level of concern," said Yankees manager Joe Girardi. "That's the bottom line. He's been asymptomatic, but he hasn't thrown."

The Yankees are yet to establish a timetable for Chamberlain's return. According to Girardi, the 25-year-old will have to throw a bullpen session before the team will clear him to pitch in another game.

"Joba said functionally he’s fine," Girardi told the Post. "But I think they might give him a couple extra days. They just want to go slow and make sure they’re doing the right thing."

It's worth noting that fellow Yankee pitcher Sergio Mitre is also suffering from an injury to his oblique, but did not need to have an MRI and is still on track to throw a bullpen on Wednesday.

After being told that the extra medical attention for Joba gives the impression that his injury may be more serious than originally thought, Yankees general manager Brian Cashman would only respond, "Maybe it is."

Cashman, who spoke with team doctors on Monday after they had a chance to look at the MRI, originally told reporters Chamberlain had a "strained oblique," which would imply that there's a muscle tear. He corrected himself later, however, saying the doctors used the term "injured oblique."